1. Field of the Invention
The present invention relates to the field of reception, and more particularly, to a circuit for determining whether a received signal is a high definition signal or an analog broadcast signal.
2. Description of the Related Art
Recently, in the United States, a test of a xe2x80x9cGrand Alliancexe2x80x9d (GA) advanced television (ATV) system which is a digital television transmission system has been completed as a new television standard which can replace a conventional analog NTSC. The GA-ATV system, standardized by an advanced television system committee (ATSC) (GA-HDTV or GA-VSB), employs a vestigial side band (VSB) modulation method which is a digital transmission method.
However, even with the start of HDTV broadcasts, the conventional NTSC cannot help but coexist. A receiver must have a structure in which it is possible to simultaneously watch the HDTV broadcasts and the NTSC TV broadcasts. Namely, since the same channel can be broadcast in either NTSC TV or HDTV, depending on the area, a structure in which it is possible to watch the two types of broadcasts is necessary. In general, a simulcast receiver which receives an HDTV signal and an NTSC TV signal can be comprised of a tuner, an HDTV signal processor and an NTSC TV signal processor for separately processing the HDTV signal and the NTSC TV signal, and a display. Therefore, in order to display either the HDTV signal or the NTSC TV signal using a single display, it is necessary to determine whether the currently received signal is a HDTV signal or a NTSC TV signal. Also, in order to display whether the channel selected by the user is the HDTV channel or the NTSC TV channel in the receiver receiving the HDTV signal, a circuit for determining whether the currently selected signal is the HDTV signal or the NTSC TV signal is necessary.
It is an object of the present invention to provide a circuit for determining whether a received signal is a high definition digital signal or an analog broadcasting signal.
It is another object of the present invention to provide a method of determining whether a received signal is a high definition digital signal or an analog broadcast signal.
To achieve the first object, a detector of a circuit for discriminating between received signals detects a peak signal based on a degree of correlation between a received signal and a reference signal. A generator shows that the received signal is a high definition signal having a predetermined digital signal format if the peak signal is detected in a predetermined period and shows that the received signal is a signal of an analog broadcast method if the peak signal is not detected in the predetermined time.
To achieve the second object, there is provided a method for discriminating whether a received signal is a high definition signal having a digital format or a signal of an analog broadcast method, comprising the steps of detecting a peak signal based on a degree of correlation between a received signal and a reference signal and generating a discrimination signal showing that the received signal is a high definition signal if the peak signal is generated in a predetermined period and showing that the received signal is a signal of an analog broadcast method if the peak signal is not detected in the predetermined period.